Ferruginous pygmy owl

The ferruginous pygmy owl (Glaucidium brasilianum) is a small owl that breeds in south-central Arizona and southern Texas in the United States, south through Mexico and Central America, to South America into Bolivia, Paraguay and Argentina.

Ferruginous pygmy owl
Cactus ferruginous pygmy owl
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Glaucidium
Species:
G. brasilianum
Binomial name
Glaucidium brasilianum
(Gmelin, 1788)

In Central America and South America, it is the most widely distributed pygmy owl and is probably one of the most numerous owl species in those areas. It is found in a wide range of semi-open wooded habitats in these areas.

Taxonomy

This species is a part of the larger family Strigidae of owls, known as typical owls. This family contains most species of owls.

Trinidad, as well as other localities, have endemic subspecies of the Glaucidium brasilianum owl. Recent genetics work has found substantial differences in ferruginous pygmy owls from different regions and members of the northern ridgwayi group are sometimes considered a separate species, the Ridgway's pygmy-owl (Glaucidium ridgwayi).

Description

This species is crepuscular, but often hunts by day. It hunts a variety of birds, lizards, mammals, and insects. The flight is often undulating in motion, similar to that of many woodpecker species.

It can be readily located by the small birds that mob it while it is perched in a tree (up to 40 birds of 11 species have been recorded mobbing one owl).

Appearance
Glaucidium brasilianum in Mexico

The ferruginous pygmy owl is small, typically 15 cm (5.9 in), and stocky with disproportionately large feet and talons. The crown has elongated white/buff streaks, the wing coverts have white spots, and the underparts are heavily streaked white. There are prominent white supercilia above the facial disc. There are dark two spots on the nape, often termed "false eyes" by birders.

Otherwise, its overall color is highly variable, ranging from grey-brown with a black-and-white barred tail to rich rufous with a uniform rufous tail. Sexes are similar with females slightly larger and often more reddish.

Call

The call is a whistled hoo-hoo-hoo-hoo, usually in E flat. It is easily imitated, and is used by birdwatchers to attract small birds intent on mobbing the pygmy owls.

Breeding and incubation

The Glaucidium brasilianum mating season is from late winter to early spring. It is a cavity nesting bird (tree and columnar cactus cavities), laying 1-7 white eggs. Incubation is 28 days, with 27–30 days to fledging.

Subspecies

There are multiple different subspecies of the ferruginous pygmy-owl. The type subspecies, G.b.brasilianum, is found in south Amazonian Brazil to east Paraguay, Uruaguay and northeast Argentina. G.b.medianum lives in the tropical lowlands of north Columbia. G.b.phaoenloides can be seen in tropical north Venuezuela, Trinidad, and the Guianas. G.b.margaritae is endemic to Isla Margarita in Venezuela, from which it takes its name. Two subspecies, G.b.duidae and G.b.olivaceum, inhabit the tepuis of south Venezuela (Mt.Duida and Mt. Auyan-Tepui), respectively. G.b stranecki lives in south Uruaguy to central Argentina. G.b.ucalayae is found in the east base of the Andes of southeast Colombia to Peru and north Bolivia.

Conservation

The northernmost subspecies, G. b. cactorum, commonly called the cactus ferruginous pygmy owl, was a listed Endangered species under the U.S. Endangered Species Act. This protected it in south-central Arizona from loss of habitat and buffel grass fires. Buffel grass catches fire very easy, which spreads to cacti, burning the owl's primary habitat.

Its range extends over the border into Sonora, Mexico. Glaucidium brasilianum was delisted in 2006.

References
  1. BirdLife International (2016). "Glaucidium brasilianum". The IUCN Red List of Threatened Species. IUCN. 2016: e.T61815999A95181606. doi:10.2305/IUCN.UK.2016-3.RLTS.T61815999A95181606.en. Retrieved 14 January 2018.
  • ffrench, Richard (1991). A Guide to the Birds of Trinidad and Tobago (2nd ed.). Comstock Publishing. ISBN 0-8014-9792-2.
  • Hilty, Steven L (2003). Birds of Venezuela. London: Christopher Helm. ISBN 0-7136-6418-5.
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